The present invention relates to devices for placing a gaseous fluid in contact with a washing liquid for purposes such as removing gaseous components and/or solid impurities from the gaseous fluid as well as for purposes such as cooling the gaseous fluid.
As is well known, flowing gaseous fluid frequently contains impurities in the form of gaseous components as well as solid particles, and these impurities must be removed before the fluid is discharged or reused. In practice, situations are often encountered where the gaseous fluid contains so much solid components that it is advisable to remove the latter before the gaseous fluid enters a washer or scrubber.
Numerous wet washer or scrubber designs for gaseous fluids are known. Many of these employ so-called filler beds through which the gaseous fluid must pass either so that washing liquid encounters the gaseous fluid in a counterflow arrangement or so that the washing liquid is in the form of a jet which flows concurrently with the gaseous fluid. While such designs are considered as operating satisfactorily, they have the drawbacks of clogging the filler beds and requiring an exceedingly large space.
Also, so-called diffuser washers or scrubbers are commonly used, wherein by reducing the width of the tube or duct through which the gas flows, a Venturi is formed accelerating the gas flow to provide a high velocity for the gas while at the same time the washing liquid is fed into the flowing gas to achieve a good contact between the flowing gas and the washing liquid. Designs of this type require large amounts of power, and in addition they are expensive with respect to the cost of the apparatus.
There are also so-called S-wave washers which are utilized as wet washers wherein the washing liquid and the gaseous fluid both enter a passage formed by an S-shaped tube, so that the gas and washing liquid are contacted with each other by way of such a construction. One of the known embodiments of this type is such that the gas flow which is to be purified is brought into contact with a foaming washing liquid, the gas being required to pass through a foam bed, whereupon a drop separation which is as complete as possible is provided.
One step which is performed by every wet washer is the separation of droplets from the gaseous flow, inasmuch as in connection with the washing operations droplets are invariably formed and these droplets must be removed from the gas. The number of such droplets which are formed is of course greater, the more complete the contact between the gas and the washing liquid. On the other hand, of course, a large number of droplets is desirable inasmuch as the impurities present in the gaseous flow are of necessity bound to these droplets. The drop separator is therefore connected subsequent to the wet washer at an appropriate location, usually in advance of the blower. Various types of devices are provided to perform the operations of drop separators, such as traps, grills which rapidly change the direction of flow, or certain types of designs which are formed with grooves. Also, filter mats are used as droplet separators. All of the above constructions, however, have the drawback that the liquid droplets clog the drop separator, with the result that impurities escape undesirably or there is an insufficient separation of droplets. There are also known prior art drop separators wherein the gas flow becomes so slow that droplets become separated, for example, on the walls of the column. Cyclone separators also have been used for the purpose of droplet separation. All of the above mentioned washer-droplet separator designs have large dimensions, while creating one particular problem with respect to the washing or scrubbing operations and a second particular problem with respect to the separation of droplets.